NASA - Transiting Exoplanet Survey Satellite ( TESS ) updates

[jebbo]

There's a question I had at the beginning I can't find the answer to. Will they be targeting some of Kepler's discoveries to compare results between the two? It seems like the extra data might help reduce the SNR, or whatever they call the optical version, for both.

Yes, pretty sure TESS re-observed the Kepler field in year 2 though I don't think I've seen any published results yet.

Edit: sectors 14 & 15

Because Kepler was looking at fainter stars and TESS is looking at brighter ones, there are only a few hundred which can really be looked at by both. This paper looks examines what more this will tell us: https://arxiv.org/abs/1810.02826

--- Tony

[Star One]

Potential Giant World Circling Tiny Star:

[Star One]

TESS’s Northern Sky Vista:



Its primary mission is now complete & it swaps back to the Southern Sky for its extended mission.

[Star One]

The TESS Objects of Interest Catalog from the TESS Prime Mission

We present 2,241 exoplanet candidates identified with data from the Transiting Exoplanet Survey Satellite (TESS) during its two-year prime mission. We list these candidates in the TESS Objects of Interest (TOI) Catalog, which includes both new planet candidates found by TESS and previously-known planets recovered by TESS observations. We describe the process used to identify TOIs and investigate the characteristics of the new planet candidates, and discuss some notable TESS planet discoveries. The TOI Catalog includes an unprecedented number of small planet candidates around nearby bright stars, which are well-suited for detailed follow-up observations. The TESS data products for the Prime Mission (Sectors 1-26), including the TOI Catalog, light curves, full-frame images, and target pixel files, are publicly available on the Mikulski Archive for Space Telescopes.

https://arxiv.org/abs/2103.12538

[Star One]

Two new gaseous planets found by citizen scientists

Two new gaseous planets have been found orbiting a sun-like star 352 light-years from Earth -- and citizen scientists helped discover them while collaborating with astronomers.

The two exoplanets, which are planets that orbit stars outside of our solar system, are called planet b and planet c. They orbit a star known as HD 152843, which has a similar mass to our sun but is 1.5 times bigger and brighter.

Citizen scientists were able to help discover these planets by participating in Planet Hunters TESS. This NASA-funded project, available on the Zooniverse website, includes more than 29,000 people around the globe. It allows people to help search for exoplanets using data from NASA's Transiting Exoplanet Survey Satellite, or TESS mission.

https://edition.cnn.com/2021/06/22/world/exoplanets-nasa-citizen-science-scn/index.html

[bolun]

NASA’s TESS Discovers Stellar Siblings Host ‘Teenage’ Exoplanets

Thanks to data from NASA’s Transiting Exoplanet Survey Satellite (TESS), an international collaboration of astronomers has identified four exoplanets, worlds beyond our solar system, orbiting a pair of related young stars called TOI 2076 and TOI 1807.

TOI 2076 and TOI 1807 reside over 130 light-years away with some 30 light-years between them, which places the stars in the northern constellations of Boötes and Canes Venatici, respectively. Both are K-type stars, dwarf stars more orange than our Sun, and around 200 million years old, or less than 5% of the Sun’s age. In 2017, using data from ESA’s (the European Space Agency’s) Gaia satellite, scientists showed that the stars are traveling through space in the same direction.

Astronomers think the stars are too far apart to be orbiting each other, but their shared motion suggests they are related, born from the same cloud of gas.

[Rondaz]

TESS Maps Red Giants Across the Sky

[Rondaz]

TESS Tracks a Giant’s Pulsations

[Rondaz]

Tuning Into a Trio of Red Giants

[Star One]

Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit

We report the discovery of five transiting companions near the hydrogen-burning mass limit in close orbits around main sequence stars originally identified by the Transiting Exoplanet Survey Satellite (TESS) as TESS Objects of Interest (TOIs): TOI-148, TOI-587, TOI-681, TOI-746, and TOI-1213. Using TESS and ground-based photometry as well as radial velocities from the CORALIE, CHIRON, TRES, and FEROS spectrographs, we found the companions have orbital periods between 4.8 and 27.2 days, masses between 77 and 98 MJup, and radii between 0.81 and 1.66 RJup. These targets have masses near the uncertain lower limit of hydrogen core fusion (∼73-96 MJup), which separates brown dwarfs and low-mass stars. We constrained young ages for TOI-587 (0.2 ± 0.1 Gyr) and TOI-681 (0.17 ± 0.03 Gyr) and found them to have relatively larger radii compared to other transiting companions of a similar mass. Conversely we estimated older ages for TOI-148 and TOI-746 and found them to have relatively smaller companion radii. With an effective temperature of 9800 ± 200 K, TOI-587 is the hottest known main-sequence star to host a transiting brown dwarf or very low-mass star. We found evidence of spin-orbit synchronization for TOI-148 and TOI-746 as well as tidal circularization for TOI-148. These companions add to the population of brown dwarfs and very low-mass stars with well measured parameters ideal to test formation models of these rare objects, the origin of the brown dwarf desert, and the distinction between brown dwarfs and hydrogen-burning main sequence stars.

https://arxiv.org/abs/2107.03480

[Star One]

An accreting white dwarf displaying fast transitional mode switching

Abstract
Accreting white dwarfs are often found in close binary systems with orbital periods ranging from tens of minutes to several hours. In most cases, the accretion process is relatively steady, with significant modulations only occurring on timescales of ~days or longer1,2. Here we report the discovery of abrupt drops in the optical luminosity of the accreting white dwarf binary system TW Pictoris by factors up to 3.5 on timescales as short as 30 minutes. The optical light curve of this binary system obtained by the Transiting Exoplanet Survey Satellite (TESS) clearly displays fast switches between two distinct intensity modes that probably track the changing mass accretion rate onto the white dwarf. In the low mode, the system also displays magnetically gated accretion bursts3,4,5, which implies that a weak magnetic field of the white dwarf truncates the inner disc at the co-rotation radius in this mode. The properties of the mode switching observed in TW Pictoris appear analogous to those observed in transitional millisecond pulsars6,7,8,9,10, where similar transitions occur, although on timescales of ~tens of seconds. Our discovery establishes a previously unrecognized phenomenon in accreting white dwarfs and suggests a tight link to the physics governing magnetic accretion onto neutron stars.

https://www.nature.com/articles/s41550-021-01494-x

Source: https://phys.org/news/2021-10-astronomers-white-dwarf.amp

[Star One]

TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf

Thanks to the relative ease of finding and characterizing small planets around M dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current paucity of planets in long-period orbits around M dwarfs make such objects particularly compelling as they provide clues about the formation and evolution of these systems. In this study, we present the discovery of TOI-2257 b (TIC 198485881), a long-period (35 d) sub-Neptune orbiting an M3 star at 57.8pc. Its transit depth is about 0.4%, large enough to be detected with medium-size, ground-based telescopes. The long transit duration suggests the planet is in a highly eccentric orbit (e∼0.5), which would make it the most eccentric planet that is known to be transiting an M-dwarf star. We combined TESS and ground-based data obtained with the 1.0-m SAINT-EX, 0.60-m TRAPPIST-North and 1.2-m FLWO telescopes to find a planetary size of 2.2 R⊕ and an orbital period of 35.19 days. In addition, we make use of archival data, high-resolution imaging, and vetting packages to support our planetary interpretation. With its long period and high eccentricity, TOI-2257 b falls in a novel slice of parameter space. Despite the planet's low equilibrium temperature (∼ 256 K), its host star's small size (R∗=0.311±0.015) and relative infrared brightness (Kmag = 10.7) make it a suitable candidate for atmospheric exploration via transmission spectroscopy.

https://arxiv.org/abs/2111.01749

Source:

https://phys.org/news/2021-11-astronomers-sub-neptune-exoplanet-orbiting-nearby.html

[Star One]

This study re-confirms that Proxima b does not transit it’s host Star from our viewpoint, and in fact no transits at all were discovered in the data for any other planet that may exist in the system larger than the size of Mars.

No Transits of Proxima Centauri Planets in High-Cadence TESS Data

Proxima Centauri is our nearest stellar neighbor and one of the most well-studied stars in the sky. In 2016, a planetary companion was detected through radial velocity measurements. Proxima Centauri b has a minimum mass of 1.3 Earth masses and orbits with a period of 11.2 days at 0.05 AU from its stellar host, and resides within the star's Habitable Zone. While recent work has shown that Proxima Centauri b likely does not transit, given the value of potential atmospheric observations via transmission spectroscopy of the closest possible Habitable Zone planet, we reevaluate the possibility that Proxima Centauri b is a transiting exoplanet using data from the Transiting Exoplanet Survey Satellite (TESS). We use three sectors (Sectors 11, 12, and 38 at 2-minute cadence) of observations from TESS to search for planets. Proxima Centauri is an extremely active M5.5 star, emitting frequent white-light flares; we employ a novel method that includes modeling the stellar activity in our planet search algorithm. We do not detect any planet signals. We injected synthetic transiting planets into the TESS and use this analysis to show that Proxima Centauri b cannot be a transiting exoplanet with a radius larger than 0.4 R⊕. Moreover, we show that it is unlikely that any Habitable Zone planets larger than Mars transit Proxima Centauri.

https://arxiv.org/abs/2110.10702

[Rondaz]

TESS has found a new representative of the brown dwarf desert

09:59 Dec 20 2021

The TESS space telescope has found a new massive brown dwarf, whose properties place it in an underexplored area - the brown dwarf desert. Scientists hope that further investigation of this object will help to understand exactly how such sub-stellar bodies are formed. A preprint of the work is available on the ArXiv.org website.

If you look at the properties of brown dwarfs, which are considered intermediate objects between stars and giant planets, you can notice the lack of bodies with a mass of 35-55 Jupiter masses, located less than three astronomical units from the parent stars of the main sequence. This phenomenon is called the desert of brown dwarfs, and it may be associated with different mechanisms for the formation of brown dwarf companions with low and high mass. In addition, this may be due to the peculiarities of the dynamic interaction of brown dwarfs of different masses with their stars. However, so far, scientists do not have enough observational data for such objects to understand their origin.

A group of astronomers led by Caleb I. Cañas from the University of Pennsylvania reports the discovery of a new massive brown dwarf TOI-2119.01, which has become another representative of the brown dwarf desert. It was originally found by the TESS space telescope using the transit method, and later the discovery was confirmed using ground-based telescopes.

The mass of the parent star, which became the red dwarf, is 0.53 solar masses, and the radius is 0.51 solar radius. The  brown dwarf has a brightness temperature of 2,100 Kelvin and a mass of 67 Jupiter masses. It has been classified as an early L-type dwarf with a radius of 1.11 that of Jupiter. The orbit of TOI-2119.01 is highly elongated (eccentricity 0.3362), the dwarf makes one revolution around the star in just 7.2 Earth days, and one revolution around its axis - in 13.2 days.

The age of the dwarf has been estimated at 0.7-5.1 billion years, while evolutionary models of brown dwarfs usually consider a period of less than one billion years of life for such objects. Due to the fact that the exact age of TOI-2119.0 is still difficult to establish, it is ill-suited for imposing a constraint on theoretical models, so observations will continue. In addition, there may be a third body in the system, but this is yet to be verified.

Earlier, we talked about how the minimum mass for burning lithium in brown dwarfs did not fit into the model.

Alexander Voytyuk

https://nplus1.ru/news/2021/12/20/brown-dwarf-m-dwarf

[Star One]

NASA’s Transiting Exoplanet Survey Satellite has now identified more than 5,000 possible exoplanet candidates – TESS Objects of Interest, or TOIs – mostly from a faint star search led by Michelle Kunimo, a postdoc at MIT. While TOIs are, by definition, unconfirmed, astronomers are confident additional observations will add to TESS’s list of known exoplanets.

“This time last year, TESS had found just over 2,400 TOIs. Today, TESS has reached more than twice that number — a huge testament to the mission and all the teams scouring the data for new planets. I’m excited to see thousands more in the years to come!”

It will take additional observations by astronomers around the world to confirm whether a TOI is, in fact, an actual exoplanet. Three such confirmations were announced at the American Astronomical Society’s winter meeting earlier this month.

A team led by Samuel Grunblatt, a postdoctoral fellow at the American Museum of Natural History and the Flatiron Institute in New York City, found three gas giants in TOI data. The planets have some of the shortest-period orbits around subgiant or giant stars yet found and one of them, TOI-2337b, likely will be consumed by its host star in less than a million years.

https://astronomynow.com/2022/01/24/astronomers-mining-an-increasingly-rich-trove-of-tess-exoplanet-data/

[redliox]

For the extended mission happening now, what kind of plan is TESS following?  There were several options ranging from repeating the prior pattern to scanning thin strips of the sky intensely.  Any specifics on where it's pointing itself now?

[Yiosie]

For the extended mission happening now, what kind of plan is TESS following?  There were several options ranging from repeating the prior pattern to scanning thin strips of the sky intensely.  Any specifics on where it's pointing itself now?

The observing strategy and timeline for the current extended mission is listed here:

https://heasarc.gsfc.nasa.gov/docs/tess/extended.html

TESS is currently observing "Sector 48" at "an ecliptic latitude of +54°."

[Rondaz]

TESS has found a hot super-Earth around a very close red dwarf

09:55 11 Feb. 2022

The TESS space telescope has discovered a new hot super-Earth, which is located in a red dwarf system very close to the Sun. Further studies of this object can help astronomers understand the origin of the sub-Neptune desert - the lack of planets close to stars with masses of 1.4-2 Earth masses. The preprint of the work is published on the website arXiv.org.

One of the problems in exoplanetology has become the nature of the sub-Neptune desert . This is the name given to the observed lack of planets with masses of 1.4-2 Earth masses that are close to their stars, which separates super-Earths and mini-Neptunes. It is still unclear exactly what mechanisms lead to the formation of these types of planets and why the desert phenomenon occurs. Perhaps rocky super-Earths are born as a result of photoevaporation of the outer shells of mini-neptunes rich in hydrogen, or another mechanism for the loss of mass of the atmosphere. To understand this, scientists need to increase the sample of known exoplanets of these types and determine their parameters with great accuracy.

A team of astronomers led by Jonas Kemmer from the University of Heidelberg announced the discovery of the exoplanet GJ 3929b in the M-dwarf system, located 51.6 light-years from the Sun. Initially discovered by the TESS space telescope using the transit method, the discovery was subsequently confirmed using the CARMENES, SAINT-EX, LCOGT and OSN ground-based telescopes, which also helped to determine the parameters of the object.

The radius of the planet GJ 3929b was estimated at 1.15 Earth radii, and the mass at 1.21 Earth masses. This gives a bulk density value of 4.4 grams per cubic centimeter, which is comparable to Earth's average density, so the object could be a rocky exoplanet. A year on the planet lasts 2.61 Earth, it is at an average distance from its star of about 0.0026 astronomical units. The equilibrium temperature of GJ 3929b is estimated at 569 kelvin, which means that it belongs to the category of hot super-Earths.

The brightness of the parent star (which is one third smaller than our own) and the size of GJ 3929b make the exoplanet an interesting target for future research with the James Webb Space Telescope, which will be able to find its atmosphere, if any. In addition, there may be another exoplanet in the system with an orbital period of 14.303 days, however this has yet to be confirmed.

Earlier, we talked about how scientists found a hot Neptune in the Neptune Desert, another mysterious feature in a sample of known exoplanets.

Alexander Voytyuk

https://nplus1.ru/news/2022/02/11/tess-hot-super-earth

[Rondaz]

TESS finds two rocky exoplanets around a red dwarf very close to the Sun

21:32 30 Apr. 2022

Astronomers using ground-based and space telescopes have discovered two rocky exoplanets that are 2-3 times heavier than the Earth near the red dwarf HD 260655 close to the Sun. They are expected to be explored by the James Webb Space Telescope in the future. A preprint of the work is available at arXiv.org.

Dwarf stars of the spectral type M are of particular interest to astronomers - planets with radii from one to four Earth radii are often found around such luminaries, and cases of detection of multiplanetary systems are not uncommon. If we take into account that observations of such stars make it possible to obtain fairly accurate estimates of the mass and radius of exoplanets orbiting them, then it becomes possible to determine how diverse the volumetric compositions of terrestrial exoplanets are and whether they have atmospheres.

A team of astronomers led by Rafael Luque of the University of Chicago announced the discovery of two exoplanets around the bright red dwarf HD 260655, which is 32.6 light-years from the Sun. The discovery was made by the transit method using the TESS space telescope and confirmed by the radial velocity method using the HIRES and CARMENES receivers mounted on ground-based telescopes.

The star has a mass of 0.43 solar masses and a radius of 0.43 solar radii, its age is estimated at 2–8 billion years, and its effective temperature is 3803 kelvin. The closest exoplanet to the star, HD 260655b, has a radius of 1.24 Earth radii and a mass of 2.14 Earth masses. This gives a volume average density of the planet of 6.2 grams per cubic centimeter, slightly more than Earth's average density. A year on HD 260655b lasts 2.77 days, the average distance from the star is estimated at 0.03 astronomical units, and the equilibrium temperature is 709 kelvin.

The exoplanet HD 260655c has a radius of 1.53 Earth radii and a mass of 3.09 Earth masses. The bulk density of the exoplanet is 4.7 grams per cubic centimeter. A year on HD 260655c lasts 5.7 days, the average distance from the star is estimated at 0.047 astronomical units, and the equilibrium temperature is 557 kelvin.

The researchers concluded that HD 260655 is unique in terms of comparative studies of rocky exoplanets. This is the third system closest to the Sun, containing an M-dwarf and several planets that periodically pass across the disk of the star. It is expected that in the future the James Webb Space Telescope will observe the newly discovered objects, which will look for their atmospheres.

Earlier we talked about how astronomers confirmed the existence of an Earth-like planet near Proxima Centauri.

Alexander Voytyuk

https://nplus1.ru/news/2022/04/30/exoplanets-rocky

[Rondaz]

TESS Finds New Companion Exoplanet Inside Hot Jupiter's Orbit

10:33 30 May 2022

Astronomers using the TESS space telescope have discovered a new exoplanet system in which an exoplanet companion is located inside the orbit of hot Jupiter. WASP-132c is the fourth such object, which does not fit into the high-eccentricity migration scenario that explains the formation of most hot Jupiters. The preprint is available at arXiv.org.

Since the discovery of the first exoplanet around a sun-like star at the end of the last century, objects like hot Jupiters have been one of the great mysteries of exoplanetology. These planets are characterized by radii greater than 8 Earth radii, orbital periods less than 10 days and represent a class of objects that have no analogues in our solar system. Traditional theories cannot explain the existence of gas giants so close to their parent stars, so scientists have developed new scenarios for the formation of such objects, such as migration in the circumstellar disk or the processes of gravitational interaction and scattering of planets. In particular, there is evidence that many of the hot Jupiters originally formed outside the snow line .in the system and then migrated closer to the star. However, none of the currently available scenarios can satisfy all model constraints derived from observational data, so the main pathways for the formation of hot Jupiters are still poorly understood.

One curious property of hot Jupiters that may indicate the path of formation is their uniqueness as planets in their system, although they may have distant companions. This absence of nearby companions is predicted by a high-eccentricity migration formation mechanism. In this case, the planet is transferred to an eccentric orbit due to the snow line under the influence of some gravitational perturbations, and eventually the orbit becomes circular and very close to its star. At the same time, such a mechanism leads to scattering and possible ejection from the system of other planets.

Of the roughly 500 confirmed hot Jupiters to date, only three have been found to be exceptions - WASP-47, Kepler-730 and TOI-1130. In these, hot Jupiters have at least one close planetary mass companion. Thus, the migration scenario with high eccentricity is unlikely; most likely, the systems were formed due to the migration of protoplanets inside the circumstellar disk closer to the star at the stage of their formation.

A team of astronomers led by Benjamin J. Hord of the University of Maryland announced the discovery of the fourth system containing a hot Jupiter and a companion planet close to it. We are talking about the orange dwarf WASP-132, with a mass of 0.78 solar masses, which is located at a distance of about 400 light years from the Sun in the constellation. The system was monitored by the TESS space telescope, which found the companion exoplanet using the transit method, and astronomers also used archival observational data from the CORALIE spectrograph of the ground-based EULER telescope to confirm the discovery.

The TESS data made it possible to refine the parameters of the hot Jupiter WASP-132b, found back in 2016 by the ground-based SuperWASP telescope. This exoplanet has a mass of 0.41 Jupiter masses, a radius of 0.754 Jupiter radii, and an orbital period of 7.13 days. Inside its orbit is the super-Earth WASP-132c, which has a radius of 1.85 Earth radii, an orbital period of 1.01 days and an upper mass limit of 37.35 Earth masses.

Dynamic modeling shows that the system is dynamically stable for a time scale of 100 million years. The scientists note that this discovery suggests that a mechanism other than the high-eccentricity migration scenario may play a significant role in the formation of hot Jupiters, and in the case of WASP-132, further observations are needed to refine exoplanet masses and confirm the discovery of WASP-132c.

Earlier, we talked about how scientists found an ultra-hot Jupiter falling on a star and for the first time recorded radio emission from such a planet.

Alexander Voytyuk

https://nplus1.ru/news/2022/05/30/companion-wasp-132-b